2-halogeno-5-nitro-benzene-1.4-dicarboxylic acids and process of making same



Patented Nov. 17,

UNITED STATES PATENTS-OFFICE HANS SGHINDHELM, OF FRANKIEOBT-ON-THE-MAIN-FECHENHETM, GERMANY, AS-

SIGNOR TO GENERAL ANILINE wonxs, me, on new ong-1v. Y., a companion OF DELAWARE 2-EALOGENO-5-NITRO-IBENZENE-IA-DICARIBOXYLIG Aoms mundane or Mime NoDrawing. Application filed. November 9, 1928, sensitiv .sl aeiaend n eeimen l November i1; 192a.

The present invention relates to 2-halogeno-5-nitrobenzene-1.4-dicarboxylic acids and to a process of making the same. f

I have found that nitro-halogen-terephthalic acids are easily obtained by treating mono-halogen-terephthalic acids with a nitrating agent. This is a surprising fact since terephthalic acid itself could hitherto be nitrated onlyunder very extreme conditions,

for instance, by means of a great excess of fuming nitric acid and a great'quantity of fumin sulfuric acid (Berichte der ,deutsch. chem. @esellschaft, vol. 10, page 145 Liebigs Annalen, vol. 121, page 90; Chem. Zentralblatt 1912, Vol. I, page 1711).

My process is carried out with an especially favorable result by acting with a mixtureof nitric and sulfuric acid on a mono-halogenterephthalic acid dissolved in sulfuric acid.

The new 2-halogeno-5-nitrobenzene-1 .4- dicarboxylic acids, which are easily obtainable by my process, correspond to the for mula OOOH Hal

OOH

They are very reactive compounds. For instance they yield with the aid of a reduclng agent 2-halogen'o-5-aminobenzene-1.4 dicar- H parts being by weight and all temperatures in Centrigrade degrees, but I wish it to be understood that I am not limited to the particular products or reaction conditions mentioned therein.

Emm

admits of mo no -chloro-terephthalic acid v( obtainable-by treating 1.4-ldime-thyl-2-chloro-benzene with chlorine while exposed to light and saponifying 1a Chloro-terephthalic hexachloride thus formed; see Example 1 of U. S: application Serial No. 318,314, filed November 9,192.8) are dissolved at about 90 vin2Q0ipa'rtsgof sulfuric: acid of66? Be. {The mass is cooled to room temperature. Then 28 parts of a miX-tureof nitric and sulfuric acid containing %of HNO are quickly dropped in, whileiwellistirring. The tem-v perature arises to about the reaction mixture becoming a clear solution. After stirring for still a short time, the solution is allowed to cool. At about 50, the new nitrocompound separates, in a crystalline form.

It is isolated by introducing the reactionmass 65 into ice. The precipitate thus formed is filtered, washed vand dried. The new 2-chloro 5=nitrobenzene-l;4 dicarboxylic acid thus obtained corresponds to theform'ula I .oooH

,oon It crystallizes from alcohol of 50% inlong nearlycolorless'needles-melting at about 265? @YJEWMP Z Q 1...; 24.5 parts of mono-bromo -terephthalic acid "(obtainable by treating lj.'4-'dimethyl-2-. bromo benzene-With. bromine while" exposed to light and saponifying the bromo-terephthalic hexabromide thus formed; see EX- mple 3 of U. S, application Serial No.

318,314, filed November 9, 1928) are dissolved in 125 parts of sulfuric acid mono-hydrate. At about 40 14 parts of a mixture of nitric and sulfuric acid containing 50% of HNO are;slowlyia trqduceplr. .The temperen1r .1 arises to about 48. I Then the 'mass is gradually heated to 80 and dissolves thereby toa clear solution. From this solution the reaction product separates in the cold and is worked up as described in Example 1. The

lized from formic acid lanceolate leaflets melting at 260 to 262 (1., soluble in organic solvents and in hot Water.

In testimony whereof, I aflix my signature.

' HANS SCHINDHELM.

new 2-bromo-5-nitrobenzene-1.4-dicarboxylicV acid thus obtained corresponds to the formula OOH I t crystallizes from formic acid in lanceolate leaflets melting at 260262, -I-claiinf- Y I 1. A process for preparing 2-halogeno 5 nitrobenz ene-1.4-dicarboxylic acids which 7 comprises causing a2 ha'logeno-benzene 1:4

dicarboxylic acid to react wi-th a mixture of nitric and sulfuric acid in a sulfuric acid solution. a

- 2. -A proces's for preparing'2 chloro 5r-ni- =trobenzene-1.4=-'dicarboxylic acid which comprises causing 2-chloro-benzene-lxkdicarboxylic acid to react with a mixture of nitric and-sulfuric acid in a sulfuric acid solution; ii 3. As new compounds'the-2 halogeno-5-ni- 'trobenzene-l/l-dicarboxylic acidsof the formula ooon rial OOH which compounds are nearly colorless crystallized substances, having vdefinite melting points,soluble gin organic solvents and hot =4. Asv a new compoundthe 2-chloro-5-nitrobenzene-1.l-dicarboxy1ic acid..o f the formula,

' coon "which compoundrepresents when crystallized from dilute alcohol long nearly colorless I p .oon 1 -05 twhiCh C0mP0l1nd' rep n when 

